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Type:
Public Security Vulnerability
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Resolution: Fixed
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Priority:
High
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Affects Version/s: 8.9.0, 8.9.1, 8.9.2, 8.9.3, 8.9.4, 9.1.0, 9.0.1, 8.9.5, 9.0.2, 9.0.3, 8.9.6, 8.9.7, 9.1.1, 8.9.8, 9.2.0, 9.2.1, 9.4.0, 9.3.1, 9.2.2, 9.3.2, 9.2.3, 9.4.1, 9.2.4, 9.2.5, 9.2.6, 9.5.1, 9.5.2, 9.5.3, 9.2.7, 10.1.0, 9.2.8, 10.0.2, 10.0.3, 9.5.4, 9.2.9, 10.1.1, 10.2.0, 9.2.10, 10.1.2, 9.2.11, 9.2.12, 10.2.1, 9.2.13, 10.2.2, 9.2.14, 10.2.3, 9.2.15, 10.2.6, 9.2.17, 10.2.7, 9.2.19, 10.2.10, 10.2.11, 9.2.20, 9.2.21, 10.2.13, 10.2.14, 9.2.22, 10.2.15, 9.2.23
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Component/s: None
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8.7
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High
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CVE-2026-12816
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Atlassian (Internal)
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CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
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BASM (Broken Authentication & Session Management)
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Confluence Data Center
This High severity BASM (Broken Authentication & Session Management) vulnerability known as CVE-2026-12816 was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center.
This BASM (Broken Authentication & Session Management) vulnerability, with a CVSS Score of 8.7 and a CVSS Vector of CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber allows an unauthenticated attacker to perform actions as another user.
Atlassian recommends that Confluence Data Center and Server customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:
- Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.24
- Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.17
See the release notes (https://confluence.atlassian.com/doc/confluence-release-notes-327.html). You can download the latest version of Confluence Data Center and Server from the download center (https://www.atlassian.com/software/confluence/download-archives).
The National Vulnerability Database provides the following description for this vulnerability: In Bouncy Castle for Java before 1.85, IESEngine stream-mode MAC forgery via length-dependent KDF split. This issue also affects Bouncy Castle for Java LTS before 2.73.12.